From bark of Geissospermum vellosii Allem., Apocynaceae: Hesse, Ann. 202, 141 (1880). Structure: Puisieux, LeHir, Compt. Rend. 252, 902 (1961); Janot, Tetrahedron 14, 113 (1961). Crystal structure: A. Chiaroni, C. Riche, Acta Crystallogr. 35B, 1820 (1979). Pharmacology: M. M. Aurousseau, Ann. Pharm. Fr. 19, 175 (1961). On hydrolysis with HCl splits into geissoschizine and geissoschizoline, q.v.